Surkhi Mortar is a mixture of lime, surkhi and water. It is lime mortar in which sand has been substituted by surkhi for economy and strength.

Note – Surkhi is finely powdered burnt clay and generally made from slightly underburnt bricks. Good surkhi should be perfectly clean and free from any admixture of foreign substances and should not contain particles retained on IS Sieve No.9 more than 10% by weight, Surkhi like sand is largely used in preparing mortar, concrete, plaster, etc. for economic considerations.

other types of mortars,

Lime Mortar
Cement Mortar
Gauged Mortar (or Combination Mortar)